1. Field of the Invention
This invention relates to a tree injection system and more particularly to an apparatus for injecting liquid chemicals directly into the trunk of a tree, the apparatus having a tapered, wedge-shaped needle on the end of an injection tip having a liquid-conducting passageway in the center of the needle leading to an ejector hole which will conduct liquid chemicals to the outer surface of the needle.
2. Description of the Related Art
Tree injection is the operation of making a cut in a tree and then placing a dose of liquid chemical into the cut. There are several known methods by which this operation may be done. Generally, a cut is made manually by means of an ax or other such hand tool. The cut must be of such a shape and angle as to allow the introduced chemical to remain in the cut while the tree absorbs and transports the chemical throughout the tree. To efficiently accomplish this operation, the cut must be of sufficient size to accommodate the chemical injector. This often results in damage being done to the tree itself, which is acceptable if the goal is to eventually kill the tree, but completely unacceptable if the goal is to improve the health of the tree.
Furthermore, many of the prior art methods of tree injection involve a two-step operation which can be time consuming and involve considerable manual effort. Also, as the operation involves two steps, there is a delay between making the cut into the tree and introducing the chemical to the cut, which is critical as trees have the ability to quickly heal up incisions protecting them from entry of bacteria or other such harmful organisms.
An example of the prior art which attempts to address these problems is Murphy, U.S. Pat. No. 5,046,281, which discloses an attachment for a handgun with a moveable piston to which is attached a blade to form a cut in a tree, and a fluid injection means which instantaneously supplies a fluid dosage to the cut. The fuel to operate the handgun, together with the fluid to be applied to the cut, are preferably provided in a backpack. While this invention applies liquid instantaneously when the cut is formed, the problem is that the cut is formed by a blade being thrust into the tree thus opening a large hole and causing damage to the surrounding tree tissue. Furthermore, to operate the apparatus, an operator must carry a backpack which holds the fuel and fluid to be injected. This situation does not present a problem when an operator is injecting one tree a day, but on such places as tree farms, an operator may inject hundreds or thousands of trees in a day, involving considerable walking and bending. Carrying such a backpack can result in various degrees of back and leg strain, due to the additional weight thereof. There is therefore a need for a relatively lightweight tree injection apparatus which can inject trees while causing a minimum of damage to the tree tissue.
Other examples of the prior art have used other means of injecting plants, such as needles or the like. Examples of such art are found in Mauget, U.S. Pat. No. 3,304,655, and Barber, U.S. Pat. No. 2,116,591; both disclose injection systems having a needle. However, the problem encountered in utilizing both examples of the prior art is that before the needle may be inserted into a tree, a hole must be formed in the tree, or the needle will be plugged by tree fiber when it is inserted. Generally, at least a ⅛-inch hole needs to be drilled in the tree to insert the needles of the above inventions, which causes a great deal of damage to a tree, which is not a good way to save a tree. Moreover, both of these examples require a two-step operation to achieve injection of a tree.
Finally, one other example of the prior art which addresses this problem is Tucker, U.S. Pat. No. 3,608,239, which discloses a tree killing poison injector nozzle comprising a tube having a wedge-shaped end portion for entering a cut formed in a tree. The opposing sides of the wedge-shaped end are cut away to define an opening at each of its sides. A poison directing guard, surrounding the tube, forms laterally open channels lying in the plane of the wedge-shaped end. Once again, however, such an injection system is fine for use if the goal is to kill the tree. If the goal is to improve the health of the tree, however, use of the Tucker invention surely will not achieve the desired end. Furthermore, the cut formed by use of the Tucker device is much larger than is desirable to prevent harm to the tree. Finally, fluid is released from nozzles a substantial distance behind the tree cutting edge, thus resulting in a deeper cut having to be made, causing more damage to the tree.
Applicant's earlier patent, U.S. Pat. No. 5,239,773, solved many of the problems associated with the prior art tree injection systems. It has been found that it would be advantageous if the injection tip and needle thereon could be left in the tree, after the liquid chemical is injected into the tree, until such time as the liquid chemical has been absorbed by the tree and that it would also be advantageous if the person performing the injection method could readily determine if the liquid chemical had been absorbed by the tree prior to removing the injection tip and needle from the tree.